Minimal residual disease (MRD) detection with translocations and T-cell receptor and immunoglobulin gene rearrangements in adult acute lymphoblastic leukemia patients: a pilot study

Objective: Monitoring minimal residual disease has become increasingly important in clinical practice of ALL management. Break-point fusion regions of leukaemia related chromosomal aberrations and rearranged immunoglobulin (Ig) and T cell-receptor (TCR) genes are used as leukaemia specific markers in genetic studies of MRD.Material and Methods: A total of 31 consecutive patients with newly diagnosed ALL were screened for eligibility criteria. Of those 26 were included in the study. One patient with partial response following induction therapy and four patients who were lost to follow-up after induction were excluded from the study; thus 21 patients were evaluated for MRD by using polymerase chain reaction (PCR), heteroduplex analysis, sequencing and quantitative real time PCR techniques. Results: Chromosomal aberrations were detected in 5 (24%) of the patients and were used for MRD monitoring. Three patients had t(9;22) translocation, the other 2 had t(4;11) and t(1;19). MRD-based risk stratification of the16 patients analysed for Ig/TCR rearrangements revealed 3 low-risk, 11 intermediate-risk and 2 high-risk patients.Conclusion: MRD monitoring is progressively getting to be a more important predictive factor in adult ALL patients. As reported by others confirmed by our limited data there is a good correlation between MRD status and clinical outcome in patients receiving chemotherapy. The pilot-study presented here is the first that systematically and consecutively performs a molecular MRD monitoring of ALL patients in Turkey

No contribution of GSTM1 and GSTT1 null genotypes to the risk of neutropenia due to benzene exposure in Southeastern Brazil

Exposure to benzene has been associated with haematological diseases such as neutropenia (NEB) and acute myeloid leukaemia (AML). We tested whether the null genotypes of the GSTM1 and GSTT1 genes, involved in benzene inactivation, altered the risk for NEB in southeastern Brazil. Genomic DNA from 55 NEB patients and 330 controls was analysed by multiplex-polymerase chain reaction. The frequency of the GSTM1, GSTT1 and combined null genotypes was similar in patients and controls (GSTM1, 27.3% vs. 38.8%, p = 0.16; GSTT1, 25.5% vs. 19.7%, p = 0.24; GSTM1/GSTT1, 12.7% vs. 6.7%, p = 0.26; respectively). The distribution of genotype classes in NEB patients was similar to normal controls, suggesting that GSTM1 and GSTT1 null genotypes make no specific contribution to the risk of NEB. As the GSTM1 and GSTT1 null genotypes were previously associated with increased risk for AML in Brazil and elsewhere, we hypothesise that different thresholds of chemical exposure relative to distinct GSTM1 and GSTT1 genotypes may determine whether AML or NEB manifests in benzene exposed individuals from southeastern Brazil. Although indicative, our results still require support by prospective and large scale epidemiological studies, with rigorous assessment of daily chemical exposures and control of the possible contribution of other polymorphic genes involved in benzene metabolism

New CNV Regions Identified in ITP Provide Evidence for Genetic Predisposition

Abstract Immune thrombocytopenia (ITP) is an autoimmune disease resulting from inhibition of megakaryopoiesis and destruction of platelets by platelet reactive autoantibodies. Adult-onset ITP usually exhibits a relapsing chronic course and is often associated with other disorders of autoimmune or infectious origin, including systemic lupus erythematosus (SLE), lymphoproliferative diseases, common variable immunodeficiency (CVID) disease, and human immunodeficiency virus (HIV) infection. The exact pathophysiology of ITP has not been fully elucidated. Heterogeneity in disease presentation and in response to immunosuppressive therapy suggests different underlying mechanisms; and thus justifies the investigation of relevant genetic associations. Here we tried to unravel the genetic background of the immune dysfunction in ITP by using SNP array technology. We analyzed the blood samples of 12 adults (6 males and 6 females) with primary refractory ITP, by SNP array approach to identify candidate genomic regions. None of the patients showed clinical and laboratory findings of autoimmune diseases, malignancy or infections. All individuals were genotyped using Illumina Human HumanCytoSNP-12 BeadChip (300K). Whole genome SNP genotyping data were delineated using GenomeStudio software platform. The genotyping data was obtained by further analyzes in terms of copy number variation (CNV). In total we observed 14 CNVs in 12 patients. All CNVs were on autosomal chromosomes; 8 duplications and 6 deletions (gain 2p, 9q, 13q, 14q, 17p, 17q, 20q; loss 5q, 7p, 7q, 15q, 17q, 19q). The rearrangements sizes were between 45.42 Mb and 1.08 Mb. Moreover in five patients the duplications were in the form of mosaic structural genomic rearrangements. These mosaic duplications were found at 17q21.31 (0.2 Mb), 2p23.2 (0.34 Mb), 9q21.2 (10.89 Mb), 9q31.2 (17.77 Mb), 14q13.2 (0.37 Mb), 17p12 (1.46 Mb), 20q11.21 (14.24 Mb). None of the detected CNV regions could be demonstrated in two independent cohorts of 30 individuals with non-hematological disorders and healthy controls. Little is known on the genetic background of immune thrombocytopenia. Our aim was to investigate the impact of CNVs on the pathophysiology of ITP. We found several gains/losses in different chromosomal regions. However, the most striking result of our study was the detection of mosaic patterns that have been reported to most commonly associate with hematological cancers. These mosaic patterns may be associated with clonal expansion of T- or B-cells, leading to the immune dysfunction seen in ITP. Evaluation of the detected regions and their relation to B and T- cell clonality is ongoing. These preliminary results provide early evidence for the presence of predisposing CNVs in adult onset ITP. Disclosures No relevant conflicts of interest to declare. </jats:sec

Effects of Imatinib Mesylate on Renin-Angiotensin System (RAS) Activity During the Clinical Course of Chronic Myeloid Leukaemia

The renin-angiotensin system (RAS) is involved in cell growth, proliferation and differentiation in bone marrow in an autocrine-paracrine manner, and it modulates normal and neoplastic haematopoietic cell proliferation. This study aimed to assess expressions of the RAS components, renin, angiotensinogen and angiotensin-converting enzyme (ACE), during imatinib mesylate treatment of patients with chronic myeloid leukaemia (CML). Expressions of RAS components were studied in patients with CML at the time of diagnosis (n = 83) and at 3, 6 and 12 months after diagnosis (n = 35) by quantitative real-time polymerase chain reaction. De novo CML patients had increased ACE, angiotensinogen and renin mRNA levels and these expression levels decreased following administration of imatinib. The RAS activities were significantly different among Sokal risk groups of CML, highlighting the altered biological activity of RAS in neoplastic disorders. The results of this study confirm that haematopoietic RAS affects neoplastic cell production, which may be altered via administration of tyrosine kinase inhibitors such as imatinib mesylate